Enantioselective trifluoromethylthiolation of 4-substituted pyrazolones catalyzed by amide-based phase transfer catalysts

Enantioselective α-Trifluoromethylthiolation of Carbonyl Compounds with AgSCF3 and Trichloroisocyanuric Acid

“…Furthermore, the enantioselective introduction of a heteroatom at the C-4 position has also attracted large amounts of attention from organic chemists because of the importance of heteroatoms in medicinal chemistry . However, there is only one enantioselective approach for the synthesis of chiral SCF 3 substituted pyrazolone skeleton as far as we know . Given the importance of both the SCF 3 unit and the pyrazolone scaffold, the development of new strategies to synthesize chiral 4-SCF 3 pyrazolones is quite essential.…”

“…16 However, there is only one enantioselective approach for the synthesis of chiral SCF 3 substituted pyrazolone skeleton as far as we know. 17 Given the importance of both the SCF 3 unit and the pyrazolone scaffold, the development of new strategies to synthesize chiral 4-SCF 3 pyrazolones is quite essential. We initiated our studies by mixing the commercially available reagent TCCA (0.06 mmol) and AgSCF 3 (0.2 mmol, 3.3 equiv) in THF.…”

“…The spectral datas for 2a were consistent with previous reports. 17 (R)-4- (3,-2,5-diphenyl-4-((trifluoromethyl)thio)-2,4-dihydro-3H-pyrazol- 3-one (2b). Following the general procedure using 1b (38.6 mg, 0.1 mmol), 2b was obtained by flash chromatography (petroleum ether/ethyl acetate: 5/1) as a light yellow solid (36.9 mg, 76% yield, 85% ee 159.3,153.6,136.2,132.2,129.9,128.4 (q,J = 310.4 Hz),127.9,127.8,125.7,125.1,118.7,106.0,100.3,57.5,54.0,39.7.…”

“…The spectral datas for 2i were consistent with previous reports. 17 (R)-4- (3,. Following the general procedure using 1j (42.8 mg, 0.1 mmol), 2j was obtained by flash chromatography (petroleum ether/ethyl acetate: 8/ 1) as a light yellow solid (49.1 mg, 93% yield, 73% ee).…”

“…The spectral datas for 2j were consistent with previous reports. 17 (R)-4-Benzyl-5-phenyl-2-(4-(trifluoromethyl)phenyl)-4-((trifluoromethyl)thio)-2,4-dihydro-3H-pyrazol- 3-one (2k). Following the general procedure using 1k (39.4 mg, 0.1 mmol), 2j was obtained by flash chromatography (petroleum ether/ethyl acetate: 15/1) as a colorless oil (37.0 mg, 75% yield, 60% ee).…”